| Summary: | 碩士 === 國立臺灣科技大學 === 機械工程系 === 98 === The main purpose of the thesis is to reduce the maximum vibration level of a beam loaded by a moving mass. A damped absorber with random parameters is designed to hang on the beam such that the average maximum deflection at its mid-span is minimized or the allowance deflection based reliability is maximized. The equation of motion is derived by mean of the modal expansion theorem, considering the mass translating velocity is constant and harmonic, respectively. In the study the constant velocity, moving mass, and absorber parameters are considered as random variables, then the perturbation method and Runge-Kutta method are used to solve the statistical responses of the beam. Finally an optimal absorber parameters and hanging location is obtained by using the genetic algorithm.
Several numerical examples are illustrated, and the results show that the maximum vibration level can be suppressed up to 8% by setting an optimal absorber on the beam. The results further show that the optimal designs using the allowance deflection based reliability as an objective function is better than that using the average maximum deflection.
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